SIMULATION OF PAINTED LADY (LEPIDOPTERA-NYMPHALIDAE) AND GREEN CLOVERWORM (LEPIDOPTERA-NOCTUIDAE) DAMAGE TO SOYBEANS

Field studies were conducted during 1974-75 [Iowa, USA] to simulate painted lady, Cynthia cardui (L.), and green cloverworm, Plathypena scabra (F.), damage to soybeans. Leaf rolling, characteristic of painted lady damage, had little effect on soybean yield. Defoliation-induced yield reductions during the 2-trifoliate leaf and full-bloom stages were additive. Reductions in bean weight per plot usually resulted from reduction in the number of pods per plot. Substantial yield differences observed between treatments during 1974 and 1975 were attributed to adverse 1974 growing conditions.